This application relates to a device for protecting pier pilings and moorings and, more particularly, to a device for preventing the formation of ice about a pier piling or mooring.
Docks and the pilings supporting docks are generally subject to a seasonal existence, that is, they must be disassembled and withdrawn from the lake annually approaching winter and reconstructed each spring after the retreat of the cold weather. The phenomenom of seasonal freezing of bodies of water in northern climates causes ice to freeze about its top surface and seize any object on the water surface. Thus, the piling supports of docks and other lake-front structures and the moorings of marinas which may be immersed in the water in the winter are firmly gripped about their circumferences by the layer of ice thus formed on the top of the water.
As in warmer weather, the level of the body of water fluctuates widely during winter and does not remain at a constant level even while frozen, due to a variety of natural causes. With a change in the elevation of the ice, the firm grip which the ice retains about objects fixed in the body of water invariably causes the object to be dislodged upward from its ground support. In the case of pilings, the new upraised position in turn forces the dock or other structure supported by the piling to become warped and uneven to the extent that it is useless for bearing weight of any sort. In extreme cases, the pilings may be completely uprooted and the damage which is done to unprotected structures is an expensive annual problem. In the face of this certain rebuilding of a dock each year, dock owners customarily disassemble their dock each year, reusing the dock material the following year in order to avoid the cost of new material. This arduous task has led to the use by some of floating docks and floating moorings in marinas which are generally anchored in a rather loose fashion. The relative instability of these substitutes are tolerated only because of the unacceptability of pilings and, up to now, the unavailability of permanent pilings for docks and moorings.
Protective apparatus have also been used to isolate the piling from direct contact with the ice. In one instance, a sleeve was placed about the piling, the sleeve being freely moveable up and down the piling to thus insulate the piling from the changes in the level of the ice. While these protective sleeves worked satisfactorily for a short time, the battering absorbed by these sleeves soon deteriorated their effectiveness.